Facebook’s photo tagging suggestion feature automatically recognises friends’ faces in a photo to make it fast and easy to tag people you know on the platform. In this tutorial, Narendra Rajput deconstructed the process to see how it works, then wrote a small Ruby script to automate the process.

With use cases in chat, advertising and photo sharing, the Face.com API now estimates the age of the faces it finds in photos. The service released mood detection last July and has seen the number of developers registered on its platform double in less than a year. The age estimation is hardly perfect, but gives a guideline that joins a number of attributes the service can return from just a snapshot.